Thin Film Transistor Liquid Crystal Display (TFT-LCD) is a widely-used Flat Panel Display (FPD).
With the improvement in technologies, consumers are expecting higher picture quality from mobile devices. Currently, the conventional Twisted Nematic (TW) LCD may not provide good enough picture quality as required by the market. As a result, all manufacturers are now implementing in the mobile devices various wide viewing angle techniques having better picture qualities, such as In-Plane Switching (IPS), Vertical Alignment (VA), Advanced-Super Dimensional Switching (AD-SDS, also abbreviated as ADS).
In the ADS mode, a multi-dimensional electric field is generated with both an electric field produced at edges of slit electrodes in the same plane and an electric field produced between a slit electrode layer and a plate-like electrode layer, consequently, liquid crystal molecules at all orientations, which are located directly above the electrodes and between the slit electrodes in a liquid crystal cell, can be rotated, thereby enhancing the work efficiency of liquid crystals and increasing the light transmittance. Therefore, the ADS technology can improve the picture quality of TFT-LCDs and has advantages of high transmittance, wide viewing angle, high aperture ratio, low chromatic aberration, low response time and being free of push Mura, etc.
Currently, an array substrate is obtained through forming patterns using multiple patterning processes. Each patterning process involves the processes of masking, exposing, developing, etching and removing, where the etching includes dry etching and wet etching. The number of the patterning processes may be used to evaluate the complexity of the fabrication of the TFT-LCD array substrate. In this sense, reducing the number of patterning processes is equivalent to reducing the manufacturing cost.
It may take at least four patterning processes to form an array substrate such as a bottom gate using the currently available technologies. Such processes are complicated, costly and the production cycle is relatively long. Therefore, it is needed to reduce the number of patterning processes, thereby reducing the production cycle and cost for fabricating the array substrate.